define(["jquery"],function(jQuery){

    jQuery.extend({

        createUploadIframe: function(id, uri)
        {
            //create frame
            var frameId = 'jUploadFrame' + id;

            if(window.ActiveXObject) {
                var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');
                if(typeof uri== 'boolean'){
                    io.src = 'javascript:false';
                }
                else if(typeof uri== 'string'){
                    io.src = uri;
                }
            }
            else {
                var io = document.createElement('iframe');
                io.id = frameId;
                io.name = frameId;
            }
            io.style.position = 'absolute';
            io.style.top = '-1000px';
            io.style.left = '-1000px';

            document.body.appendChild(io);

            return io
        },
        createUploadForm: function(id, fileElementId)
        {
            //create form
            var formId = 'jUploadForm' + id;
            var fileId = 'jUploadFile' + id;
            var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
            var oldElement = jQuery('#' + fileElementId);
            var newElement = jQuery(oldElement).clone();
            jQuery(oldElement).attr('id', fileId);
            jQuery(oldElement).before(newElement);
            jQuery(oldElement).appendTo(form);
            //set attributes
            jQuery(form).css('position', 'absolute');
            jQuery(form).css('top', '-1200px');
            jQuery(form).css('left', '-1200px');
            jQuery(form).appendTo('body');
            return form;
        },

        ajaxFileUpload: function(s) {
            // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout
            s = jQuery.extend({}, jQuery.ajaxSettings, s);
            var id = s.fileElementId;
            var form = jQuery.createUploadForm(id, s.fileElementId);
            var io = jQuery.createUploadIframe(id, s.secureuri);
            var frameId = 'jUploadFrame' + id;
            var formId = 'jUploadForm' + id;
            // Watch for a new set of requests
            if ( s.global && ! jQuery.active++ )
            {
                jQuery.event.trigger( "ajaxStart" );
            }
            var requestDone = false;
            // Create the request object
            var xml = {}
            if ( s.global )
                jQuery.event.trigger("ajaxSend", [xml, s]);
            // Wait for a response to come back
            var uploadCallback = function(isTimeout)
            {
                var io = document.getElementById(frameId);
                try
                {
                    if(io.contentWindow)
                    {
                        xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
                        xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;

                    }else if(io.contentDocument)
                    {
                        xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null;
                        xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document;
                    }
                }catch(e)
                {
                    jQuery.handleError(s, xml, null, e);
                }
                if ( xml || isTimeout == "timeout")
                {
                    requestDone = true;
                    var status;
                    try {
                        status = isTimeout != "timeout" ? "success" : "error";
                        // Make sure that the request was successful or notmodified
                        if ( status != "error" )
                        {
                            // process the data (runs the xml through httpData regardless of callback)
                            var data = jQuery.uploadHttpData( xml, s.dataType );
                            // If a local callback was specified, fire it and pass it the data
                            if ( s.success )
                                s.success( data, status );

                            // Fire the global callback
                            if( s.global )
                                jQuery.event.trigger( "ajaxSuccess", [xml, s] );
                        } else
                            jQuery.handleError(s, xml, status);
                    } catch(e)
                    {
                        status = "error";
                        jQuery.handleError(s, xml, status, e);
                    }

                    // The request was completed
                    if( s.global )
                        jQuery.event.trigger( "ajaxComplete", [xml, s] );

                    // Handle the global AJAX counter
                    if ( s.global && ! --jQuery.active )
                        jQuery.event.trigger( "ajaxStop" );

                    // Process result
                    if ( s.complete )
                        s.complete(xml, status);

                    jQuery(io).unbind()

                    setTimeout(function()
                    {	try
                    {
                        jQuery(io).remove();
                        jQuery(form).remove();

                    } catch(e)
                    {
                        jQuery.handleError(s, xml, null, e);
                    }

                    }, 100)

                    xml = null

                }
            }
            // Timeout checker
            if ( s.timeout > 0 )
            {
                setTimeout(function(){
                    // Check to see if the request is still happening
                    if( !requestDone ) uploadCallback( "timeout" );
                }, s.timeout);
            }
            try
            {
                // var io = jQuery('#' + frameId);
                var form = jQuery('#' + formId);
                jQuery(form).attr('action', s.url);
                jQuery(form).attr('method', 'POST');
                jQuery(form).attr('target', frameId);
                if(form.encoding)
                {
                    form.encoding = 'multipart/form-data';
                }
                else
                {
                    form.enctype = 'multipart/form-data';
                }
                jQuery(form).submit();

            } catch(e)
            {
                jQuery.handleError(s, xml, null, e);
            }
            if(window.attachEvent){
                document.getElementById(frameId).attachEvent('onload', uploadCallback);
            }
            else{
                document.getElementById(frameId).addEventListener('load', uploadCallback, false);
            }
            return {abort: function () {}};

        },

        uploadHttpData: function( r, type ) {
            var data = !type;
            data = type == "xml" || data ? r.responseXML : r.responseText;
            // If the type is "script", eval it in global context
            if ( type == "script" )
                jQuery.globalEval( data );
            // Get the JavaScript object, if JSON is used.
            if ( type == "json" )
                eval( "data = " + data );
            // evaluate scripts within html
            if ( type == "html" )
                jQuery("<div>").html(data).evalScripts();
            //alert(jQuery('param', data).each(function(){alert(jQuery(this).attr('value'));}));
            return data;
        },

        handleError: function( s, xhr, status, e )      {
            // If a local callback was specified, fire it
            if ( s.error ) {
                s.error.call( s.context || s, xhr, status, e );
            }
            // Fire the global callback
            if ( s.global ) {
                (s.context ? jQuery(s.context) : jQuery.event).trigger( "ajaxError", [xhr, s, e] );
            }
        }
    });

    return jQuery.ajaxFileUpload();

});
